JPH05215473A - Heater - Google Patents

Abstract

PURPOSE:To obtain a heater which has excellent spalling resistance, deterioration resistance and reactivity resistance and in which a temperature can be stably raised and lowered for a long period. CONSTITUTION:An inorganic coating layer 3 is used as a support of a heat generator 2 in a laminate in which the coating layer coated on its inner surface with inorganic fiber cloth and having a bulk density of 1.0-2.0g/cm<3> is formed on an inner surface of an inorganic molded form having a bulk density of 0.3-0.8g/cm<3>. A heater has a treating vessel 1 in which a material to be treated is disposed on an inner soaking area, the laminate so disposed as to surround the vessel 1, and the generator 2 supported to the coating layer of the laminate 3, and comprises cooling means for cooling the soaking area of the vessel 1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heating device.

[0002]

2. Description of the Related Art For example, a semiconductor device manufacturing process includes various steps of heating a semiconductor wafer. For example, it is a process such as an oxidation process, a diffusion process, a CVD process, an epitaxial process, or a doping process. In an example of a heating device used for such a heat treatment, a processing container in which a semiconductor wafer that is an object to be processed is arranged, a heat insulating material arranged so as to surround the processing container, and an inner wall of the heat insulating material. And a heating element disposed in. Conventionally, a ceramic fiber is used as the heat insulating material,
As the heating element, a resistance heating element such as Kanthal (trade name) wire which is an alloy wire of iron (Fe), chromium (Cr) and aluminum (Al) has been conventionally used.

However, recently, from the viewpoint of increasing the productivity of semiconductor devices, a heating device capable of raising and lowering the temperature at high speed has been required. However, since the heating element made of Kanthal wire has a small allowable current density as described above,
It is difficult to raise the temperature at a sufficiently high speed. Therefore, the present inventor has proposed molybdenum disilicide (M
oSi ₂ ) has been considered. With this MoSi ₂ , the heat capacity is small and the temperature can be raised at high speed.

[0004]

However, when the process of raising the temperature at a high speed using a heating element made of MoSi ₂ is repeated, cracks due to spalling easily occur in the heat insulating material made of ceramic fibers, and The problem of significant deterioration occurred. The spalling is a phenomenon in which the constituent material of the heat insulating material is scattered as dust. In addition, after the semiconductor wafer is heat-treated, if the process of forcibly flowing a cooling medium into the soaking region of the processing container to cool the semiconductor wafer at high speed is repeated and particles are generated from the deteriorated heat insulating material, contamination may occur. There was also a problem causing nation. Further, there has been a problem that the heating element made of MoSi ₂ and the heat insulating material react with each other at the contact portion, and the heating element is broken.

Therefore, a first object of the present invention is to provide a heating device having excellent spalling resistance, deterioration resistance and reaction resistance. A second object of the present invention is to provide a heating device that can stably raise and lower the temperature over a long period of time.

[0006]

In order to achieve the above object, the heating device of the present invention has the following features. (1) bulk to the inner surface of the inorganic molded body density 0.3 to 0.8 g / cm ^3, bulk density the inner surface was coated with an inorganic textile cloth inorganic coating of 1.0 to 2.0 g / cm ³ It is a laminated body in which layers are formed, and the inorganic coating layer serves as a support portion of the heating element. (2) The laminated body according to (1) is characterized by being fired at a high temperature. (3) The inorganic molded body of (1) is characterized in that it is formed into a tubular shape by a plurality of divided products. (4) The inorganic molded body according to (1) above is an alumina fiber,
It is characterized by being formed from an inorganic filler and an inorganic binder. (5) The alumina fiber of (4) above contains 9% Al ₂ O ₃ .
It is characterized by containing 0 wt% or more. (6) The content of the following impurity metal element contained in the laminate of (1) is in the following range. Total of sodium (Na) and potassium (K): 2000ppm or less Copper (Cu): 50ppm or less Iron (Fe): 500ppm or less Nickel (Ni): 50ppm or less (7) The object to be treated is placed in the internal soaking region A processing apparatus comprising: a treatment container, a laminate of (1) arranged so as to surround the treatment container, and a heating element supported by an inorganic coating layer in the laminate; It is characterized in that a cooling means for cooling the soaking region is provided. (8) The heating element of (7) is molybdenum disilicide (Mo).
Si ₂ ).

[0007]

[Function] The laminated body becomes an inorganic molded body having a low bulk density,
Inorganic coating layer with a high bulk density is laminated and configured,
Moreover, since the inner surface of the inorganic coating layer is reinforced by the inorganic fiber cloth, there is no risk of cracking or peeling due to heat shock even when the temperature is raised or lowered at high speed. When the laminate is fired at a high temperature, the strain of the laminate is reduced. When the inorganic molded body is formed into a cylindrical shape by a plurality of divided products, a laminate having a precise structure can be obtained. When the inorganic molded body is formed of the alumina fiber, the inorganic filler and the inorganic binder, dust and the like are less scattered. When the alumina fiber contains 90 wt% or more of Al ₂ O ₃ , heat resistance is improved. When the content of the specific impurity metal element contained in the laminated body is suppressed to a specific value or less, the contamination becomes small. By providing a cooling means for cooling the soaking region of the processing container, it is possible to stably perform the high-speed heat treatment for a long period without deteriorating the laminate even when the temperature is raised and lowered at a high speed. Even when molybdenum disilicide (MoSi ₂ ) is used as the heating element, the reactivity with the inorganic coating layer is small and there is no risk of the heating element breaking.

[0008]

EXAMPLES Examples of the present invention will be described below. The following examples are examples in which a semiconductor wafer is used as the object to be processed, but the present invention is not limited to the semiconductor wafer, and the heating target can be arbitrarily selected. For example, it can be applied to heating of an LCD or the like.

FIG. 1 is a schematic view of a heating device according to an embodiment. 1 is a processing container, 2 is a heating element, 3 is a laminated body, 4 is a semiconductor wafer, 5 is a wafer holder, 6 is a heat retaining tube, 7 is an outer casing,
Reference numeral 8 is a base, and 9 is a lid member. The processing container 1 is made of, for example, a quartz tube, a laminated body 3 is arranged so as to surround the outer periphery thereof, and the heating element 2 is supported by the laminated body 3. As shown in FIG. 2, the laminated body 3 has a bulk density of 0.3 to 0.8 g /
The inner surface of the inorganic molded body 32 of cm ³ is coated with the inorganic fiber cloth 33 on the inner surface, and the bulk density is 1.0 to 2.0 g.
/ Cm ³ of the inorganic coating layer 31 is formed and configured. The inorganic coating layer 31 serves as a support for the heating element 2.

The bulk density of the inorganic coating layer 31 is 1.0 to
It should be in the range of 2.0 g / cm ³ . When the bulk density is less than 1.0, wind speed resistance (erosion resistance) decreases. When the bulk density exceeds 2.0 g / cm ³ , the thermal spalling resistance decreases. Alumina fibrous cloth is suitable as the inorganic fiber cloth 33 that covers the inner surface of the inorganic coating layer 31, and it is embedded in the inner surface of the inorganic molded body 32 when the material of the inorganic coating layer 31 is coated. It is affixed and suppresses the generation of cracks and particles in the inorganic molded body 32. The inorganic coating layer 31 is made of alumina fiber,
It can be formed by an inorganic filler and an inorganic binder, and the mixing ratio of these is, for example, alumina fiber /
Inorganic filler / inorganic binder = 10-15 / 40-
It is 60 / 20-40 (wt%).

As the alumina fiber, usual Al ₂ O is used.
It is possible to use those containing _three components in an amount of about 70 wt% or more, but those containing 90 wt% or more of Al ₂ O ₃ which has little heat deterioration and good fiber deterioration due to recrystallization at high temperature, In addition, short fibers that promote uniform reinforcing in a mixture of other inorganic filler and inorganic binder to promote a reinforcing effect are preferable. Specific examples of such short fibers include:
"Ruby" (Nichias, Al ₂ O ₃ / Si
O ₂ = 95/5 (wt%)). As the inorganic filler, for example, alumina powder, mullite powder or the like can be used. As the inorganic binder, for example, colloidal silica, colloidal alumina or the like can be used. As a heating element, molybdenum disilicide (MoSi)
_{When 2} ) is used, the material for the coating layer is preferably composed of a material composed of alumina fiber, alumina powder and colloidal alumina.

The hardness of the inorganic coating layer 31 is preferably high in order to enhance the spalling resistance, and for example, a Vickers hardness Hv of about 50 to 100 is preferable. The surface roughness of the inorganic coating layer 31 is preferably 20 μm or less in order to prevent the constituent materials (particles) from scattering due to dusting due to rapid heating and rapid cooling. The thickness of the inorganic coating layer 31 is 0.5 to 3 m from the viewpoint of preventing the occurrence of cracks due to thermal shock and improving the temperature rise characteristics by reducing the heat capacity.
A range of about m is preferable.

The bulk density of the inorganic molded body 32 is 0.3 to
It must be in the range of 0.8 g / cm ³ . When the bulk density is less than 0.3, high temperature (1000 ℃ or more)
The thermal conductivity at high temperature becomes large, and the heat insulating property deteriorates. On the other hand, when the bulk density exceeds 0.8, the heat capacity increases and the weight also increases. The inorganic molded body 32 is
It can be formed by an inorganic fiber, an inorganic filler, and an inorganic binder, and the mixing ratio of these is, for example, inorganic fiber / inorganic filler / inorganic binder = 20 to 65.
/ 35 to 70/3 to 10 (wt%). As the specific material of the inorganic fiber, the inorganic filler, and the inorganic binder, the same material as the inorganic coating layer 31 can be used. The thickness of the inorganic molded body 32 is, for example, 5 to 30 mm.
It is a degree.

The above inorganic coating layer 31 and the inorganic molded body 3
It is preferable that the laminate 3 with 2 is fired at a high temperature. In addition, "high temperature" means when using the heating device,
It is a temperature higher than the operating temperature at which the laminated body 3 actually reaches. For example, in the case of using a heating device for oxidation treatment or diffusion treatment of a semiconductor wafer, since the treatment temperature reaches about 1200 ° C., firing is performed at a high temperature of 1200 to 1600 ° C., for example.
By firing at such a high temperature, cracking or peeling of the dense inorganic coating layer 31 due to heat shock during use is suppressed, and spalling resistance is improved. Also,
Al ₂ O forming the inorganic coating layer 31 also from the crystal structure side
₃ , SiO ₂ becomes mullite (3Al ₂ O ₃ .2Si
O ₂ ) reduces the free SiO ₂ component,
Heat resistance is improved and molybdenum disilicide (Mo
The reaction with the heating element 2 made of Si ₂ ) is suppressed,
Prevent deterioration of the.

In the laminate 3, the total content of alkali metal sodium (Na) and potassium (K) is 2000 ppm or less, the content of heavy metal copper (Cu) is 50 ppm or less, and the heavy metal iron. Nickel (Ni) that is a heavy metal with a (Fe) content of 500 ppm or less
Is preferably 50 ppm or less. By suppressing the content of such an impurity metal element to be small, the spalling resistance of the laminate 3 is further improved and the contamination resistance is also improved.

The laminated body 3 has a cylindrical shape as a whole, but as shown in FIG. 3, it is formed by combining two semi-cylindrical shapes. The heating element 2 has a single wire U at the top and bottom.
It is bent into a letter shape and is formed into a vertically continuous Miyander shape. The heating element 2 is attached and held to the inner wall of the stack 3 by staples 21.

Specifically, it can be manufactured as follows. (1) Alumina fibers, an inorganic filler, and an inorganic binder are used to form a cylinder (inner cylinder) for the inorganic coating layer, which is vertically divided into four, and the surface of each divided body is formed. The whole surface is covered while adhering alumina cloth to the, and further baked. (2) Using an inorganic fiber, an inorganic filler, and an inorganic binder, a cylindrical body (outer cylindrical body) for an inorganic molded body is molded, and this is vertically divided into two parts. (3) Two divided bodies (inner cylinders) are arranged on the inner surface side of one half of the outer cylinder body, both are adhered, and dried to produce one laminated body. (4) A heating element is fastened to the inner surface of one of the laminates obtained in (3) above with a staple to obtain one half-divided product. (5) With respect to the other half-divided outer cylinder body, the other half-divided product is obtained in the same manner as in (3) and (4) above. (6) One half product and the other half product are combined to form a tubular body.

As the heating element 2, molybdenum disilicide (MoSi ₂ ) can be preferably used. This M
oSi ₂ can be used as a single wire and is about 180
Since it can sufficiently withstand a high temperature of 0 ° C., it is suitable as a material for a heating device that performs processing at a high temperature. Also, M
Since oSi ₂ has a small heat capacity, it is suitable for heating at a high speed, and since the stability of the electric resistance value at high temperatures is also excellent, the heating temperature is highly uniform.

It is preferable to provide cooling means (not shown) for cooling the soaking area 11 of the processing container 1. By adding this cooling means, the temperature of the processing container 1 can be lowered at high speed. As the cooling means, for example, a configuration in which a cooling gas is caused to flow in the gap 12 between the processing container 1 and the laminated body 3 can be adopted. Air or an inert gas such as nitrogen or argon can be used as the cooling gas. In the case of oxidation treatment or diffusion treatment of a semiconductor wafer, it is preferable to cool the soaking region of the processing container 1 to, for example, about 300 to 400 ° C.

The processing container 1 can be formed of, for example, quartz (SiO ₂ ). The processing container 1 has a cylindrical shape having an opening at the lower end, and a wafer holder 5
The semiconductor wafer 4 is isolated from the heating element 2 and the laminated body 3 to isolate the atmosphere of the semiconductor wafer 1 from the outside. The base 8 is made of, for example, stainless steel, and the base 8 holds the processing container 1 and the laminated body 3. The wafer holder 5 is placed on a heat insulation cylinder 6, and the heat insulation cylinder 6 is fixed to a lid member 9. On the wafer holder 5, a plurality of semiconductor wafers 4 are horizontally arranged at equal intervals. The lid member 9 is vertically reciprocally moved by an elevating means (not shown). When the lid member 9 descends, the wafer holder 5 integrally descends, and the wafer is unloaded. On the other hand, when the lid member 9 is lifted up and the processing container 1 is sealed, the loading state is established.

Although the present invention has been described based on the embodiments, the heat treatment apparatus of the present invention can be applied to any of a normal pressure process, a reduced pressure process and a vacuum process. Further, it can be applied to various heat treatments such as oxidation treatment, diffusion treatment, CVD treatment, and annealing.

[0022]

As described above, according to the present invention, the following effects can be obtained. (1) According to the invention of claim 1, a heating device having excellent spalling resistance, deterioration resistance, and reaction resistance can be obtained. (2) According to the invention of claim 2, a heating device with less distortion can be obtained. (3) According to the invention of claim 3, a precise heating device can be obtained even with a complicated structure. (4) According to the invention of claim 4, a clean heating device can be obtained. (5) According to the invention of claim 5, a clean and strong heating device can be obtained. (6) According to the invention of claim 6, a heating device excellent in contamination resistance can be obtained. (7) According to the invention of claim 7, it is possible to obtain a heating device capable of stably raising and lowering the temperature over a long period of time. (8) According to the invention of claim 8, it is possible to obtain a heating device capable of stably raising and lowering the temperature at high speed over a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a heating device according to an embodiment.

FIG. 2 is a cross-sectional view of a laminated body and a heating element according to an example.

FIG. 3 is a perspective view showing a state where a heating element is attached to the laminated body according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Processing container 11 Uniform heat area 12 Gap 2 Heating element 21 Staple 3 Laminated body 31 Inner layer 32 Outer layer 33 Inorganic fiber cloth 4 Semiconductor wafer 5 Wafer holder 6 Insulating cylinder 7 Outer casing 8 Base 9 Lid member

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshihisa Miyahara 3-2-8 Kishitani, Tsurumi-ku, Yokohama-shi, Kanagawa (72) Inventor Yoshiyuki Motoyoshi 1-6-9 Aobadai, Midori-ku, Yokohama-shi, Kanagawa

Claims (8)

[Claims] The inner surface of the 1. A mineral molding of bulk density 0.3 to 0.8 g / cm ^3, bulk density the inner surface coated with inorganic fibers made cloth of 1.0 to 2.0 g / cm ³ A heating device comprising a laminate having an inorganic coating layer formed thereon, wherein the inorganic coating layer serves as a support portion for a heating element. 2. A heating device, wherein the laminate according to claim 1 is fired at a high temperature. 3. A heating device, wherein the inorganic molded body according to claim 1 is formed into a cylindrical shape by a plurality of divided products. 4. A heating device, wherein the inorganic molded body according to claim 1 is formed from an alumina fiber, an inorganic filler and an inorganic binder. 5. The alumina fiber according to claim 4 is Al ₂ O.
A heating device containing 90% by weight or more of ₃ . 6. A heating device, wherein the content of the following impurity metal elements contained in the layered product according to claim 1 is in the following range. Total of sodium (Na) and potassium (K): 2000 ppm or less Copper (Cu): 50 ppm or less Iron (Fe): 500 ppm or less Nickel (Ni): 50 ppm or less 7. A processing container in which an object to be processed is arranged in an internal temperature-equalizing region, a laminated body according to claim 1 arranged so as to surround the processing container, and an inorganic coating layer in the laminated body. A heating device comprising: a heating element; and a cooling unit for cooling a soaking region of the processing container. 8. A heating device according to claim 7, wherein the heating element is made of molybdenum disilicide.